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F. GRINNELL.

DUPLEX VALVE.

"Patented 008. 25,1887.

(No Mode1.)

No. 872,218.V

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vUNITED Sri/irritev PATENT Ormea.

FREDERICK GRINNELL, OF PROVIDENCE, RHODE ISLAND.

DUPLEX VALVE.

SPECIFICATION forming part ot" Letters Patent No. 372,218, dated October 25, 1887.

I Application tiled December 30, 1886. Serial No. 122,983. (No model.)

lsecond or intermediate chamber into the third chamber upon the release of pressure from said third chamberrand my invention more particularly relates to such a system where the pressure` iu the third chamber, though less than that in the nrst, is made to directly control the tlow from the latter.

It is often desirable, for instance, to have a less pressure in the working or distributing pipes of a duid-pressure system than in the supply pipes or mains, or to have air-pressure in the former and water-pressure in the latter, or to have, normally, both of these conditions, and yet have the release of pressure from the working-pipes automatically open a connection to them from the supplypipe. To do this effectively it is necessary to provide an intermediate chamber having a less pressure than either of the pipes and opening into both pipes through valve-ports, the valves of which are both held closed by means acted upon by the pressure in the working or distributing pipes.

' My present invention consists of a peculiar construction of duplex check-valve'for performing this function, and its construction and operation will be best understood from a description of the accompanying drawings, in Which- Figure 1 represents aview, partly in section, of my improvement applied to a system of automatic lire extinguishers. Fig. 2 shows the device in its operative or open position. Fig. 3 shows a detail, hereinafter described.

As the invention is well adapted for use in connection with an automatic tire-extinguishing apparatus, its modeof operation Willbe better understood by a-description in connection therewith. In Patent No. 249,171, granted to me November 8, 188i, I have shown such a system, and reference is made to such patent for a more complete exposition of what is required in such an apparatus.

In Fig. 1 is shown distributing pipes 1, provided with sprinklers 2, such as are used in an apparatus of that kind. These pipes and distributers are charged with air under a light pressure by attaching an air-pump to pipe 27, 6o and a gage, 18, serves to show at any time when the pressure is up to the proper' point. The water-supply pipe 3 is connected with any suitable source of water-pressure, and betweenA it and the distributing'pipe 1, I place a chamber 65 or easing, 4, separated bya water-valve, 5, from the Water-supply pipe, and by a diaphragm,

6, and valve 7 from the distributing-pipe.

The valves 5 and 7 are made integral by means of a eonnectingstem, 8, thereby forming what may be called a duplex valve, and the port of the upper valve, 7, being through the diaphragm 6, the diaphragm, when forced down by pressure from above, has a tendency to hold both valves to their respective seats. Owing to the greater area of the diaphragm 6 and `valve 7 over the Water-valve 5, the light air-pressure in the distributing-pi pes is enabled to more than balance the greater waterpressure in the supply-pipe, and the water- 8o valve is thus held securely to its seat until such time as the pressure in the distributingpipes is relieved by the opening of one or more of the sprinklers. The valves are guided by a valve-stem, 9, passing through yokes 10, and the diaphragm 6 is similarly guided by yokes 11, attached to it and sliding on the valvestem.

The fact that the valve7 seats up against the movable diaphragm 6, iusteadot' against a 9o rigid seat, greatly facilitates the accurate fitting of the valves. It will also be seen that the valve 7 may be as small as desired, compatible with suflicieut area of opening, because it is not alone depended upon to hold the water-valve closed.

The liuid in the intermediate chamber, 4, should have a pressure less than that in the distributing-pipes 1, and in order to prevent any leakage that may occur past the valves 5 roo or 7 from increasing this pressure I provide a drip-pipe, 13, which communicates normally allow the water to iiow around it in the direc- Y tion of the arrows, but closing up against the shoulder 14.3 when the pressure becomes abnormal.

A spring, 20, is arranged to pass under'the lug 28 on the diaphragm-yoke and hold the valve from closing when it has once opened. This device is not claimed herein, as it is claimed in another case of even date herewith. A rod, 2G, also attached to the diaphragmplate, holds a washer, 2i, that is connected by wire 25 with any suitable alarm mechanism, so that when the diaphragm lifts an alarm is given as soon as the washer iies o" the rod.

The valves 5 and 7 may be inspected at any time through hand-holes in the chamber 4 by the removal of the hand-hole plugs 22.

A pipe, 1G, having a stop-cock, l5, forms a by-pass for turning water on to the intermediate chamber, 4, and distributing-pipes, when desired. A cock, 17, in pipe 12, leading from the lower partof the distributing-pipe, is used for drawing off the water above that level.

The valve-stem 9 has a shoulder, 30, that impiuges against the yoke l0 when the valves open and prevents their further motion, whereupon the diaphragm, continuing its motion, opens the port closed by valve 7.

rlhe operation of the device may now be readily understood. The pressure being removed froni the upper side of the diaphragm by the opening of any of the sprinklers, under the action of the heat of a tire, the water will be unopposed and will lift the valve 5 fromits seat, carrying with it, of course, valve 7 and diaphragm 6. rlhe water-pressure thus reaching the under side of the diaphragm will coutinue to push the same upward, even alter the shoulder 3() has reached the yoke 10 and stopped the motion ofthe valves. rlhe water will thus have a free passage past both valves into the distributing-pipes and through the opened sprinklers.

I do not claim herein, broadly, the combination whereby the light air-pressure is made lar plate, a, connected with the walls of the chamber by means of a flexible rubber sheet, b, and this is my preferred construction; but itis evident that there are equivalents that will take the place of the diaphragm and perform the same function.

Having thus described my invention, what I claim as new is- 1. rlhe combination, substantiallyas hereinbefore set forth, of a double valve with seats facing in opposite directions, a valve seat appropriate to one face of the double valve to close the opening in the supply-pipe, a second valve-seat appropriate to the other face of the double valve and mounted on a movable diaphragm, and a stop to limit the movement of the double valve when the pressure in the supply-pipe is paramount, and to permit under such pressure the movable valveseat to move away from its valve and give entrance for the water into the distributingpipes.

2. The combination, substantially as hereinbefore set forth, of two pipes or chambers, each containing fluid under pressure, an intermediate chamber having ports into both pipes and normally under a pressure less than that in either of the pipes, a movable diaphragm carrying one of the said ports, valves held against both ports by the action of the fluidprcssure on the diphragm, and a stop for limiting the play of said valves.

3. The combination of pipe 1, charged with light air-pressure, pipe 3, charged with heavier water-pressure, intermediate chambcr,4, under pressure less than either pipe, valve 5, closing a port between said chamber 4 and pipe 3, diaphragm 6, closing pipe 1, and valve 7, closing a port through diaphragm 6, the said valve 7 having a lnorc limited play than the said diaphragm, and the combined arca of said valve 7, and diaphragm (i heilig more in excess of the area of the valve 5 than the pressure in the pipe 3 is in excess of that in pipe l.

FREDERICK GRINNELL.

Vitnesses:

XV. H. TnUns'roN, W. H. KNIGHT. 

